Containers for transporting produce over long distances are wellknown. These containers are typically provided with atmospheric control systems to control the temperature and humidity of the air confined within the container. Prior art systems for controlling the humidity of the air confined within a container suffer from several disadvantages as will be discussed below.
A primary disadvantage of prior art humidity control systems is the inability to prevent damage to the system resulting from water freezing. In prior art systems, little or no provision is made to prevent water from freezing within the system. Such freezing usually causes damage to substantially rigid joints and other structures that may be effected by the slight expansion of water upon freezing. As a result, portions of these systems that come in contact with water typically suffer damage, sometimes to the point of inoperability, when the water freezes.
Further, these prior art systems have provided no provision for recycling water that has been absorbed in the air confined within the container. As is known, atmospheric control systems typically include refrigerating coils for refrigerating the air confined within the container. Water that has been absorbed in the air condenses and freezes on the refrigerating coils. To aid in maintaining the efficiency of the refrigerating coils, prior art systems have provided devices for periodically defrosting the refrigerating coils :o release water condensed thereon. Prior art humidity control systems have ignored this condensed water, permitting it to escape to the floor of the container.
The failure of prior art systems to recycle water provided to the air within the container results in a need for prior art systems to provide large reservoirs for containing water used to increase the humidity of the air. These large reservoirs are not only bulky, but are required to contain an extremely large quantity of water.
Accordingly, it is desirable to provide a humidity control system including a water flow control subsystem constructed to prevent freezing water from damaging the humidity control system. It is further desirable to provide a water control subsystem that is constructed for recycling water provided to the air confined within the container. As usual, it is desirable to provide such a water control subsystem that operates efficiently and can be provided in a cost effective manner.